All,
After some testing of two independent implementations of IPP I
believe
a clarification is required in the protocol specification. (IMHO)For
simplicity
in parsing I hope that xxx-attributes-tags should only be sent when an
xxx-attribute-sequence is present in the IPP payload. I see no reason
for a xxx-attributes-tags by itself. A data-tag by itself makes sense
to
delimit an IPP header in a data stream. Attached(PROP I) are the
modifications I suggest.
If we intend to allow xxx-attributes-tags without any associated
attributes
I believe clarification is needed. I have attached(PROP II)
modification to
clarify this.
Of course there is always "leave it alone"(PROP III).
Pete
PS Pat: Let me know when your address is updated in the IPP DL. I'll
stop cc'ing you.
_________________________
PROP I
Clarification in ipp-pro-971014.doc suggested:
Section 3.1:
picture of encoding stays the same
line 140:
"unsupported-job. The xxx-attributes-tag and xxx-attribute-sequence
may be omitted if the operation has no attributes or it may be"...
change to
"unsupported-job. The xxx-attributes-tag and xxx-attribute-sequence
MUST be omitted if the operation has no attributes or it may be"
...
line 145:
"An xxx-attributes-sequence consists of zero or more
compound-attributes."
change to
"An xxx-attributes-sequence consists of one or more
compound-attributes."
line 182(parsing diagram):
"| empty or rest of attribute | x bytes |"
change to
"| rest of attribute | x bytes |"
section 3.2:
line 202(syntax of encoding):
"xxx-attribute-sequence = *compound-attribute"
change to
"xxx-attribute-sequence = 1*compound-attribute"
section 3.6.1: no change.
_________________________
PROP II
Clarification in ipp-pro-971014.doc suggested:
Section 3.1:
picture of encoding:
"| xxx-attribute-sequence | n bytes |"
change to
"| xxx-attribute-sequence |0 to n bytes|"
line 140:
"unsupported-job. The xxx-attributes-tag and xxx-attribute-sequence
may be omitted if the operation has no attributes or it may be"...
change to
"unsupported-job. The xxx-attributes-tag and xxx-attribute-sequence
or just the xxx-attribute-sequence may be omitted if the operation
has no attributes. The tag and sequence may be"...
parsing diagram: no change
section 3.2:
line 202(syntax of encoding): No change
section 3.6.1:
line 263 to 266:
"The operation-attributes-tag SHALL precede those attributes defined
as operation attributes in the model document. The
job-attributes-tag
SHALL precede those attributes defined as job attributes in the
model
document. The printer-attributes-tag SHALL precede those attributes
defined as printer attributes in the model document. The
unsupported-job-attributes-tag SHALL precede those attributes
defined
as unsupported job attributes in the model document
Change to:
"Those attributes defined as operation attributes in the model
document
SHALL be preceded by the operation-attributes-tag. Those attributes
defined as job attributes in the model document SHALL be preceded
by
the job-attributes-tag. Those attributes defined as printer
attributes in the
model document SHALL be preceded by the printer-attributes-tag.
Those
attributes defined as unsupported job attributes in the model
document
SHALL be preceded by the unsupported-job-attributes-tag. Any of
the tags
may appear without any associated attributes."
__________________________________
Email: pzehler at channels.mc.xerox.com
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
Webster NY, 14580-9701
Voice: (716) 265-8755
FAX: (716)265-8792
__________________________________
"I always wanted to be somebody,
but I should have been more specific."
Lily Tomlin
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